Gojka Roglic

The long-term effect of lifestyle interventions to prevent diabetes in the China Da Qing Diabetes Prevention Study: a 20-year follow-up study.

BACKGROUND Intensive lifestyle interventions can reduce the incidence of type 2 diabetes in people with impaired glucose tolerance, but how long these benefits extend beyond the period of active intervention, and whether such interventions reduce the risk of cardiovascular disease (CVD) and mortality, is unclear. We aimed to assess whether intensive lifestyle interventions have a long-term effect on the risk of diabetes, diabetes-related macrovascular and microvascular complications, and mortality. METHODS In 1986, 577 adults with impaired glucose tolerance from 33 clinics in China were randomly assigned to either the control group or to one of three lifestyle intervention groups (diet, exercise, or diet plus exercise). Active intervention took place over 6 years until 1992. In 2006, study participants were followed-up to assess the long-term effect of the interventions. The primary outcomes were diabetes incidence, CVD incidence and mortality, and all-cause mortality. FINDINGS Compared with control participants, those in the combined lifestyle intervention groups had a 51% lower incidence of diabetes (hazard rate ratio [HRR] 0.49; 95% CI 0.33-0.73) during the active intervention period and a 43% lower incidence (0.57; 0.41-0.81) over the 20 year period, controlled for age and clustering by clinic. The average annual incidence of diabetes was 7% for intervention participants versus 11% in control participants, with 20-year cumulative incidence of 80% in the intervention groups and 93% in the control group. Participants in the intervention group spent an average of 3.6 fewer years with diabetes than those in the control group. There was no significant difference between the intervention and control groups in the rate of first CVD events (HRR 0.98; 95% CI 0.71-1.37), CVD mortality (0.83; 0.48-1.40), and all-cause mortality (0.96; 0.65-1.41), but our study had limited statistical power to detect differences for these outcomes. INTERPRETATION Group-based lifestyle interventions over 6 years can prevent or delay diabetes for up to 14 years after the active intervention. However, whether lifestyle intervention also leads to reduced CVD and mortality remains unclear.

The metabolic syndrome: useful concept or clinical tool? Report of a WHO Expert Consultation

This article presents the conclusions of a WHO Expert Consultation that evaluated the utility of the ‘metabolic syndrome’ concept in relation to four key areas: pathophysiology, epidemiology, clinical work and public health. The metabolic syndrome is a concept that focuses attention on complex multifactorial health problems. While it may be considered useful as an educational concept, it has limited practical utility as a diagnostic or management tool. Further efforts to redefine it are inappropriate in the light of current knowledge and understanding, and there is limited utility in epidemiological studies in which different definitions of the metabolic syndrome are compared. Metabolic syndrome is a pre-morbid condition rather than a clinical diagnosis, and should thus exclude individuals with established diabetes or known cardiovascular disease (CVD). Future research should focus on: (1) further elucidation of common metabolic pathways underlying the development of diabetes and CVD, including those clustering within the metabolic syndrome; (2) early-life determinants of metabolic risk; (3) developing and evaluating context-specific strategies for identifying and reducing CVD and diabetes risk, based on available resources; and (4) developing and evaluating population-based prevention strategies.

Cardiovascular mortality, all-cause mortality, and diabetes incidence after lifestyle intervention for people with impaired glucose tolerance in the Da Qing Diabetes Prevention Study: a 23-year follow-up study

BACKGROUND Lifestyle interventions among people with impaired glucose tolerance reduce the incidence of diabetes, but their effect on all-cause and cardiovascular disease mortality is unclear. We assessed the long-term effect of lifestyle intervention on long-term outcomes among adults with impaired glucose tolerance who participated in the Da Qing Diabetes Prevention Study. METHODS The study was a cluster randomised trial in which 33 clinics in Da Qing, China-serving 577 adults with impaired glucose tolerance-were randomised (1:1:1:1) to a control group or lifestyle intervention groups (diet or exercise or both). Patients were enrolled in 1986 and the intervention phase lasted for 6 years. In 2009, we followed up participants to assess the primary outcomes of cardiovascular mortality, all-cause mortality, and incidence of diabetes in the intention-to-treat population. FINDINGS Of the 577 patients, 439 were assigned to the intervention group and 138 were assigned to the control group (one refused baseline examination). 542 (94%) of 576 participants had complete data for mortality and 568 (99%) contributed data to the analysis. 174 participants died during the 23 years of follow-up (121 in the intervention group vs 53 in the control group). Cumulative incidence of cardiovascular disease mortality was 11.9% (95% CI 8.8-15.0) in the intervention group versus 19.6% (12.9-26.3) in the control group (hazard ratio [HR] 0.59, 95% CI 0.36-0.96; p=0.033). All-cause mortality was 28.1% (95% CI 23.9-32.4) versus 38.4% (30.3-46.5; HR 0.71, 95% CI 0.51-0.99; p=0.049). Incidence of diabetes was 72.6% (68.4-76.8) versus 89.9% (84.9-94.9; HR 0.55, 95% CI 0.40-0.76; p=0.001). INTERPRETATION A 6-year lifestyle intervention programme for Chinese people with impaired glucose tolerance can reduce incidence of cardiovascular and all-cause mortality and diabetes. These findings emphasise the long-term clinical benefits of lifestyle intervention for patients with impaired glucose tolerance and provide further justification for adoption of lifestyle interventions as public health measures to control the consequences of diabetes. FUNDING Centers for Disease Control and Prevention, WHO, the China-Japan Friendship Hospital, Da Qing First Hospital.

Mortality attributable to diabetes: estimates for the year 2010.

Country and global health statistics underestimate the number of excess deaths due to diabetes. The aim of the study was to provide a more accurate estimate of the number of deaths attributable to diabetes for the year 2010. A computerized disease model was used to obtain the estimates. The baseline input data included the population structure, estimates of diabetes prevalence, estimates of underlying mortality and estimates of the relative risk of death for people with diabetes compared to people without diabetes. The total number of excess deaths attributable to diabetes worldwide was estimated to be 3.96 million in the age group 20-79 years, 6.8% of global (all ages) mortality. Diabetes accounted for 6% of deaths in adults in the African Region, to 15.7% in the North American Region. Beyond 49 years of age diabetes constituted a higher proportion of deaths in females than in males in all regions, reaching over 25% in some regions and age groups. Thus, diabetes is a considerable cause of premature mortality, a situation that is likely to worsen, particularly in low and middle income countries as diabetes prevalence increases. Investments in primary and secondary prevention are urgently required to reduce this burden.

Diabetes and tuberculosis: the impact of the diabetes epidemic on tuberculosis incidence

BackgroundTuberculosis (TB) remains a major cause of mortality in developing countries, and in these countries diabetes prevalence is increasing rapidly. Diabetes increases the risk of TB. Our aim was to assess the potential impact of diabetes as a risk factor for incident pulmonary tuberculosis, using India as an example.MethodsWe constructed an epidemiological model using data on tuberculosis incidence, diabetes prevalence, population structure, and relative risk of tuberculosis associated with diabetes. We evaluated the contribution made by diabetes to both tuberculosis incidence, and to the difference between tuberculosis incidence in urban and rural areas.ResultsIn India in 2000 there were an estimated 20.7 million adults with diabetes, and 900,000 incident adult cases of pulmonary tuberculosis. Our calculations suggest that diabetes accounts for 14.8% (uncertainty range 7.1% to 23.8%) of pulmonary tuberculosis and 20.2% (8.3% to 41.9%) of smear-positive (i.e. infectious) tuberculosis.We estimate that the increased diabetes prevalence in urban areas is associated with a 15.2% greater smear-positive tuberculosis incidence in urban than rural areas – over a fifth of the estimated total difference.ConclusionDiabetes makes a substantial contribution to the burden of incident tuberculosis in India, and the association is particularly strong for the infectious form of tuberculosis. The current diabetes epidemic may lead to a resurgence of tuberculosis in endemic regions, especially in urban areas. This potentially carries a risk of global spread with serious implications for tuberculosis control and the achievement of the United Nations Millennium Development Goals.

Diabetes and the risk of tuberculosis: a neglected threat to public health?

Objectives: Tuberculosis (TB) remains a major global public health problem. In the past, a relationship between TB and diabetes mellitus (DM) was recognized, and its importance was acknowledged through joint treatment clinics. However, this is rarely highlighted in current research or control priorities. This paper aims to evaluate the evidence for an association between these two diseases. Methods: A Medline literature search was undertaken, supplemented by checking references and contacting experts. We critically appraised studies that quantified the association between TB and DM, and were published after 1995. We assessed study quality according to criteria such as sample size, method of selection of cases and controls, losses to follow-up, quality and method of control of confounding, and summarized the results narratively and in tabular form. Results: All studies identified statistically significant and clinically important associations, with the increase in risk or odds of TB varying between 1.5- and 7.8-fold for those with DM. Risk was highest at younger ages. Most studies had not measured and controlled adequately for potential major confounders. Discussion: There is strong evidence for an association between TB and DM, which has potential public health implications. Further well-designed studies are needed to assess the magnitude precisely.

Diabetes and associated disorders in Cambodia: two epidemiological surveys

BACKGROUND The Asia-Pacific region is thought to be severely affected by diabetes. However, reliable, standardised data on prevalence and characteristics of glucose intolerance in Asian populations remain sparse. We describe the results of two field surveys undertaken in Cambodia in 2004. METHODS 2246 randomly selected adults aged 25 years and older were examined in two communities, one rural (Siemreap) and one semi-urban (Kampong Cham). The diagnosis of diabetes and impaired glucose tolerance was based on 2-h blood glucose estimation using criteria recommended by the latest report of a WHO Expert Group. Blood pressure, anthropometry, habitual diet, and other relevant characteristics were also recorded. FINDINGS Prevalence of diabetes was 5% in Siemreap and 11% in Kampong Cham. Prevalence of impaired glucose tolerance was 10% in Siemreap and 15% in Kampong Cham. About two-thirds of all cases of diabetes were undiagnosed before the survey. Prevalence of hypertension was 12% at Siemreap and 25% at Kampong Cham. People in Kampong Cham had higher estimates of central obesity than those in Siemreap. INTERPRETATION Diabetes and hypertension are not uncommon in Cambodia. A quarter of all adults in the chosen suburban community had some degree of glucose intolerance. Since Cambodian society is relatively poor, and lifestyle is fairly traditional by international standards, these findings are unexpected.

Improving tuberculosis prevention and care through addressing the global diabetes epidemic: from evidence to policy and practice.

Diabetes triples the risk of tuberculosis and is also a risk factor for adverse tuberculosis treatment outcomes, including death. Prevalence of diabetes is increasing globally, but most rapidly in low-income and middle-income countries where tuberculosis is a grave public health problem. Growth in this double disease burden creates additional obstacles for tuberculosis care and prevention. We review how the evolution of evidence on the link between tuberculosis and diabetes has informed global policy on collaborative activities, and how practice is starting to change as a consequence. We conclude that coordinated planning and service delivery across communicable and non-communicable disease programmes is necessary, feasible, and creates synergies that will help to reduce the burden of both tuberculosis and diabetes.

Defining the research agenda to reduce the joint burden of disease from Diabetes mellitus and Tuberculosis

The steadily growing epidemic of diabetes mellitus poses a threat for global tuberculosis (TB) control. Previous studies have identified an important association between diabetes mellitus and TB. However, these studies have limitations: very few were carried out in low‐income countries, with none in Africa, raising uncertainty about the strength of the diabetes mellitus–TB association in these settings, and many critical questions remain unanswered. An expert meeting was held in November 2009 to discuss where there was sufficient evidence to make firm recommendations about joint management of both diseases, to address research gaps and to develop a research agenda. Ten key research questions were identified, of which 4 were selected as high priority: (i) whether, when and how to screen for TB in patients with diabetes mellitus and vice versa; (ii) the impact of diabetes mellitus and non‐diabetes mellitus hyperglycaemia on TB treatment outcomes and deaths, and the development of strategies to improve outcomes; (iii) implementation and evaluation of the tuberculosis ‘DOTS’ model for diabetes mellitus management; and (iv) the development and evaluation of better point‐of‐care diagnostic and monitoring tests, including measurements of blood glucose and glycated haemoglobin A1c (HbA1c) for patients with diabetes mellitus. Implementation of this research agenda will benefit the control of both diseases.

Nutrition, Diabetes and Tuberculosis in the Epidemiological Transition

Background Diabetes prevalence and body mass index reflect the nutritional profile of populations but have opposing effects on tuberculosis risk. Interactions between diabetes and BMI could help or hinder TB control in growing, aging, urbanizing populations. Methods and Findings We compiled data describing temporal changes in BMI, diabetes prevalence and population age structure in rural and urban areas for men and women in countries with high (India) and low (Rep. Korea) TB burdens. Using published data on the risks of TB associated with these factors, we calculated expected changes in TB incidence between 1998 and 2008. In India, TB incidence cases would have increased (28% from 1.7 m to 2.1 m) faster than population size (22%) because of adverse effects of aging, urbanization, changing BMI and rising diabetes prevalence, generating an increase in TB incidence per capita of 5.5% in 10 years. In India, general nutritional improvements were offset by a fall in BMI among the majority of men who live in rural areas. The growing prevalence of diabetes in India increased the annual number of TB cases in people with diabetes by 46% between 1998 and 2008. In Korea, by contrast, the number of TB cases increased more slowly (6.1% from 40,200 to 42,800) than population size (14%) because of positive effects of urbanization, increasing BMI and falling diabetes prevalence. Consequently, TB incidence per capita fell by 7.8% in 10 years. Rapid population aging was the most significant adverse effect in Korea. Conclusions Nutritional and demographic changes had stronger adverse effects on TB in high-incidence India than in lower-incidence Korea. The unfavourable effects in both countries can be overcome by early drug treatment but, if left unchecked, could lead to an accelerating rise in TB incidence. The prevention and management of risk factors for TB would reinforce TB control by chemotherapy.